Introduction: Breathlessness persists in about 50% patients following acute PE despite anticoagulation. Chronic thromboembolic pulmonary hypertension (CTEPH) occurs in only a small proportion of cases, but early diagnosis is critically important.
Aims: Utility of CPET in identifying CTEPH.
Methods: CPET was performed in 57 patients with persisting symptoms >6 months of anticoagulation. RV strain and PE size were assessed from original imaging.
Retrospective analysis was undertaken to identify whether any indices could distinguish patients with subsequent CTEPH diagnosis using one way ANOVA of 3 groups; Gp 1 (No CTED/CTEPH), Gp 2 (Chronic thromboembolic disease), Gp 3 (CTEPH).
Results: Sex, age, BMI and smoking history did not differ but ANOVA identified significant CPET differences between groups: post-hoc multiple comparisons identified several indices differentiating Group 3 from Group 2 and Group 1, tabulated as mean (sd). There was no significant difference between groups for AT, AT %VO2, VO2/WR, BR%, Peak HR, Peak HR%, SPO2 peak, RV strain.
| Index | Gp1 | Gp2 | Gp3 | p value |
| Peak VO2 | 17.90(5.38) | 20.56(9.90) | 14.31(4.35)* | 0.041 |
| O2pulse | 11.88(3.60) | 13.32(4.41) | 10.19(2.48)* | 0.043 |
| VE/VCO2 at AT | 34.06(4.25)$ | 33.23(4.08) | 41.93(5.28)* | <0.001 |
| VE/VCO2 slope | 29.95(5.10)$ | 32.39(6.61) | 40.06(6.61)* | <0.001 |
| VE/VO2 at AT | 29.47(4.24) | 29.77(4.43) | 36.27(3.92)* | <0.001 |
| PETCO2 at AT | 37.82(4.04)$ | 36.45(3.71) | 30.53(3.89* | <0.001 |
| PETCO2 at peak | 33.58(4.40)$ | 32.36(5.39) | 27.75(4.49)* | 0.002 |
| PE size | 2.53(1.17) | 3.27(0.70)# | 3.06(0.93) | NS |
| Post hoc mulitple comparisons: *Gp3 different to Gp2; $Gp3 different to Gp1; #Gp2 different fo Gp1. | ||||
Conclusions: CPET differentiates Gp 3 from Gp 1 and 2, but cannot differentiate Gp 2 from Gp 1.